[alsa-devel] [PATCH] US-122L Driver, v0

Clemens Ladisch cladisch at fastmail.net
Thu Nov 8 17:14:51 CET 2007

Karsten Wiese wrote:
> snd-usb-audio uses number_of_packets equalling multiples of 8 currently
> when transfering over USB 2.0, no?
> If so, with above patch that "multiples of 8"-thing could go away and
> snd-usb-audio could achieve up to 8 times less userspace-activation-jitter
> in low latency setups like 128 frames/period, 2 periods.

I'm using the 8-microframes alignment because ehci-hcd configures the
controller to interrupt at most every 1 ms.  It has a module option to
change this, but as long as snd-usb-audio cannot detect a lower setting,
it would not make sense to allow shorter periods.


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